Steam boiler



Patented June 2 6, 1934- UNITED STATES PATENT OFFIEE STEAM BOILER Marcel Ehlinger, Mulhouse, France, assignor to the firms of Sccit Alsacienne de Constructions Mecaniques, Mulhouse, France, and

Aktiebolaget Atmos, Stockholm, Sweden 1 Claim.

The present invention relates to a steam boiler of the kind comprising one or more rotating steam generators, each of which consists of a central tube and an annular set of external tubes arranged around said central tube.

In this kind of steam boiler, the feed-water which is pie-heated in any convenient feed-water pre-heater to the boiling temperature is led into a collector, wherefrom it is distributed through the individual rotating units by virtue of gravity. The steam produced in the rotating units is also allowed to flow into the water collector and passes therefrom into the superheaters.

If the steam output of the rotating units is a small one or if the water and steam tubes as well as the necessary stuffing boxes interposed between the rotating and the stationary parts are largely proportioned, the weight of the water will be sufficient to ensure the introduction of water into the rotating units, even at a relatively small height of the water collector above the latter. If, however, the rotating units have a high steam output and if, simultaneously, the feeding pipes are of small diameter for the sake of economy and 'light structure (for example in view of the stresses of dilatation) the weight of the water will not be sumcient to cause the introduction of water into the rotating units at the usual diiTerences in height of the latter and the water collector. In order to compensate the considerable pressure losses in the water feeding and steam leading-off conduits, the water collector must be placed at a good height above the rotating units, depending on the density of the water and the steam. This height which amounts in ordinary cases to about 10 to 15 m, is therefore rather important and requires unusual sizes for the boiler house, without mentioning the drawbacks involved by the long conduits.

The present invention now consists in the arrangement of a pump between the water collector and the rotating units of the boiler, this pump being designed to draw out the feed-water from the water collector and to press it into the rotating units of the boiler.

In order that the invention may be more fully understood, a boiler plant according to the invention will now be described, by way of example, and with reference to the accompanying drawing, wherein Figure 1 is a longitudinal and Figure 2 a transverse section of a boiler having two rotat ing steam generators, the number of which is however not limited.

The feed-water flows through the tube 1 into the water collector 2, in which the water is maintained at the desired level by means of an automatic or non-automatic feed-water regulator. From the collector 2 the water is drawn out by a feed pump 4 through a tube 3, said feed pump 4 being interposed between the collector 2 and two rotating steam generators 5 to be supplied therefrom with water. The rotating steam generators comprise each, as is well known, a central tube 5 and an annular set of external tubes 5 communicating at one end through pipes 5 with the central tube 5, the whole being rotatably mounted in suitable bearings 5 At the other end the external tubes 5 communicate through pipes 5 with a hollow bush 12 rigidly connected to the central tube .5 and rotatably supported in one of said bearings 5 to simultaneously serve as rotating shaft. The said bush l2 freely opens into a stationary chamber 13 to which is connected the delivery pipe 4 of the pump 4. The steam which is produced in each generator escapes from the central tube 5 thereof through the pipes 6 and 7, whereof the pipe 6 extends axially through said bush 12 and said chamber 13, and flows into the collector 2, wherefrom it is led away through the pipe 8 to the working places, eventually after having been conducted through a superheater, whereas the water supply to all the steam tubes is efiected by one and the same pump 4.

The water displacing pump 4 is constructed in such a manner that it will be largely sufficient for the desired steam output of the rotating units and even be in excess so as to obtain a water circulation through the system. In the central tube 5 of the latter, a water level 9 will be formed, the height of which is maintained nearly constant by the fact that if the water level should rise, the steam which escapes through the pipe 6 draws along with it a more or less great quantity of water.

It is evident, from an arrangement of this kind, that the maintenance of a predetermined water level in the water collector 2 will ensure the feeding of all the rotating units. The water collector 2 may also very well be placed below the rotating units. The distribution of the water among these units may either take place behind the pump, which may be common to all units, or there may be provided as many feeding pumps as rotating units.

The invention is applicable in connection with any arrangement of the rotating units within the combustion chamber and irrespectively of the relative height and the number thereof. Moreover, the invention is independent of the kind of feeding pump which is used, centrifugal pumps, however, being preferably employed.

When the feed-water contains impurities, as is generally the case, the same will return to the water collector 2, which may be provided to this effect with a suitable draining device.

If the rotating units are provided with scraping chains arranged within their tubes to scrape off the deposits as they are formed therein, the deposited masses will finally be collected within the collector 2, in which the purity of the water may be maintained at the desired degree by means of suitable draining.

The water collector is preferably arranged in such a manner that the draining therein will be effected in the region where the water contains the most impurities. It is advantageous to provide a partition wall 10 within the water collector 2 in upright position, in order to form therein two juxtaposed compartments, one of which serves to receive the water coming back from the rotating units, whilst the other serves to receive the water admitted from the preheater to the collector 2 and is connected to the suction pipe 3 of the pump 4, the water mentioned in the first place containing naturally more impurities than the last mentioned one. Inthis case draining will take place for example at 11, the impurities being discharged from the generator in draining service through the tube '7 having its exit in the collector 2 above the second or additional compartment arranged aside the main or fresh water supply compartment connected to the pump suction pipe 3, so that they will be collected in said additional compartment of the collector, wherefrom they may be drained from time to time, whilst in normal service the steam is led away through the pipe 8.

What I claim is:-

A steam boiler comprising a rotating steam generator, water feeding collector divided by a partition into two lower compartments, a main and an additional one, a water supplying tube connected to said main collector compartment, a feeding pump for the generator, a pipe connecting said pump to said main water supply collector compartment, said steam generator having a central tube and an annular set of external tubes communicating with said central tube, a rotatably mounted hollow bush rigidly connected to the latter and serving as supporting shaft therefor, conduits connecting said bush to said external tubes, a stationary casing providing a chamber in open connection with said bush, a pipe connecting the delivery side of said pump to said chamber, a steam discharging and drain" ing tube extending through said bush and chamber, a discharge pipe connected With said steam discharging and draining tube and opening into the water collector above the second or additional collector compartment separated from the main water supply compartment of the collector, and a steam abduction pipe at the top of said water collector.

MARCEL EHLINGER. 

